Piezoelectric materials can have various properties. In particular, polarized piezoelectric materials can produce electric potentials between electrodes attached at opposing sides in response to vibration of the piezoelectric material. In addition, electrical potentials of a predetermined frequency can be applied to electrodes attached at opposing sides of a polarized piezoelectric material to produce mechanical vibrations in the material.
In conventional manufacturing processes, piezoelectric materials can be formed in bulk by sintering oxides, including but not limited to lead oxide, zirconium oxide, and titanoxide into a block or a cylinder. Prior to sintering, the oxides are bound together with an organic binder such as wax or nylon. The sintering process can take place in a kiln at high temperature, e.g., 1200 degrees Celsius. The sintering process is similar to that used in forming ceramics.
Blocks of piezoelectric material can be cut into thin slices that are brittle because of the characteristics of the piezoelectric material. The thin slices can then be polarized using an electric field. Electrodes are attached to the thin piezoelectric slices so as to cover an entire surface of the slice or form an interdigitated pattern on a surface of the slice. Conventionally, sets of electrodes can be connected on the same or opposing sides of the slice of piezoelectric material. A set of interdigitated electrodes can also be connected to the same or opposing sides of the slice of piezoelectric material by way of finger-like electrodes. These finger-like electrodes can be connected to the same or opposing surfaces of the material. The polarized piezoelectric slices with attached electrodes are often referred to as “piezoelectric elements.”
Piezoelectric elements can be affixed to objects to convert mechanical energy, in the form of vibration, to electrical current or to convert electrical current to mechanical energy, in the form of vibration. Piezoelectric elements known in the art are brittle and, therefore, poorly suited for application to uneven surfaces. Similarly, subjecting piezoelectric elements known in the art to stress results in fracture.
Piezoelectric elements can be used in a variety of applications, including but not limited to racquets (such as tennis, racquetball, squash), and ski apparatus. It is desirable to use piezoelectric elements for in these applications to dampen or dissipate vibrations as well as other applications.
For example, depending upon where a tennis ball strikes the strings of a tennis racquet, conventional tennis racquets generate vibrations in the frame and handle. These vibrations can negatively affect the performance of a tennis racquet, and can be unpleasant or physically problematic for the user. Therefore, it is desirable to dampen the vibrations in the frame and handle of tennis racquets.
Skis and snowboards can go faster and generally turn better when a surface of the ski or snowboard is heated. Therefore, it is desirable to heat a surface of a ski or snowboard or similar device.
Additional benefits of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.